sympy2hwy 0.1.0

Translate SymPy expressions to Google Highway SIMD expressions

sympy2hwy

sympy2hwy translates SymPy expressions into Google Highway SIMD function calls. It emits the explicit function API instead of overloaded C++ operators, so generated expressions remain usable with sizeless SIMD types such as SVE and RVV.

from sympy import symbols
from sympy2hwy import hwycode

a, b = symbols("a b")
hwycode(a + b)
# 'hn::Add(a, b)'

Security warning

Never pass untrusted strings to hwycode or the command-line interface.

String inputs are parsed with sympy.sympify. SymPy's string parsing uses Python evaluation mechanisms and is not a sandbox. A malicious expression can execute arbitrary Python code with the permissions of the running process.

For input originating outside your trust boundary, do not use this package's string interface or CLI.

Installation

python -m pip install -e .

The project requires Python 3.10 or newer and SymPy 1.14 or newer.

Python API

from sympy2hwy import HighwayPrinter, hwycode

hwycode("x - y / 3")
# 'hn::Sub(x, hn::Mul(hn::Set(d, 0.3333333333333333), y))'

hwycode("exp(x)", use_contrib=True)
# 'hn::Exp(d, x)'

hwycode("exp(x)", use_contrib=True, fast=True)
# 'hn::FastExp(d, x)'

hwycode("x + 2", namespace="project::", tag="df")
# 'project::Add(x, project::Set(df, 2))'

The public function is:

hwycode(
    expr,
    namespace="hn::",
    tag="d",
    fast=False,
    use_contrib=False,
)

• expr may be a trusted string or a pre-built SymPy Expr.
• namespace is emitted exactly as provided, including the trailing ::.
• tag selects Highway overloads and broadcasts numeric constants.
• use_contrib=True enables functions from hwy/contrib/math.
• fast=True selects available Fast*, approximate reciprocal, and approximate reciprocal-square-root operations. Functions without a fast equivalent remain accurate when contrib support is enabled.

HighwayPrinter exposes the same configuration for direct printer use.

Command line

The CLI is intended only for trusted expressions:

sympy2hwy 'a + b'
sympy2hwy --contrib --fast 'exp(x) + cos(y)'
sympy2hwy --namespace 'project::' --tag df 'x / y'

Supported expressions

Core mode supports symbols, numeric broadcasts, arithmetic, integer powers, square roots, absolute value, min/max, modulo, floor, and ceiling. Contrib mode adds supported trigonometric, inverse, hyperbolic, exponential, logarithmic, error, gamma, cube-root, and general-power functions.

SymPy rationals are converted to binary64 decimal literals before being broadcast. This intentionally loses exact rational precision.

Expressions without a direct Highway translation raise UnsupportedExpressionError. This includes comparisons, boolean expressions, Piecewise, matrices, calculus objects, complex values, infinities, NaN, and unknown functions. The output is a single C++ expression; callers must provide the required Highway includes, namespace alias, tag, and vector declarations.

Development

python -m pytest

The test suite covers the printer API, core and contrib mappings, fast mode, strict rejection, configuration options, and CLI behavior.

Publishing

Pushing any Git tag, or manually running the Build and publish workflow in GitHub Actions, tests the package, builds both wheel and source distributions, checks their metadata, and publishes them to PyPI.

Publishing uses PyPI Trusted Publishing rather than a stored API token. Before the first release, configure a trusted publisher for the sympy2hwy PyPI project with these values:

• Owner and repository: this GitHub repository's owner and name.
• Workflow filename: publish.yml.
• Environment: pypi.

Create a GitHub environment named pypi; adding required reviewers is strongly recommended, especially because the workflow supports manual publication. The version in pyproject.toml must be new on PyPI before triggering a release.

git tag v0.1.0
git push origin v0.1.0